tl;dr - Right now, what annoys me the most with Easy Diffusion is the startup time and friction, and how Easy Diffusion isn't actually "easy" anymore - the default model (SD 1.5) is bad, users take too long to get productive, and new models require a lot of configuration. That's what v4 aims to bring under control.
Started the long-pending rewrite of Easy Diffusion's server code. v4 intends to replace the Python (and PyTorch) based server with a simple C++ version. The reason for rewriting the server in C++ is to achieve sub-second startup time for the UI, and to reduce the download size (won't need to distribute Python along with Easy Diffusion) or mess with conda/venv etc. And it's also something that I want to do for personal taste, i.e. de-bloating what doesn't need to be bloated.
Spent a few days prototyping a UI for Easy Diffusion v4. Files are at this repo.
Notes on two directions for ED4's UI that I'm unlikely to continue on.
Worked on a few UI design ideas for Easy Diffusion v4. I've uploaded the work-in-progress mockups at https://github.com/easydiffusion/files.